PHP OOP programming question-Collection of common programming errors

Hi I was given a link to php classes. I am trying to make a domain availability checker. I managed to get a domain whois class from there but having a problem running it. I have included the class in my page, instatiated it and tried to run the example code. When i load it, it is displaying the class on my site and then below saying: Fatal error: Class ‘domain’ not found in C:\wamp\www\tes.php on line 8. I don’t get it my path is obviously right if it can display the class on screen.

Heres my code. Please bear in mind this is the example code that was supplied with the class.